@article {66,
	title = {Nutations in growing plant shoots as a morphoelastic flutter instability},
	journal = {Philosophical Transactions of the Royal Society A},
	volume = {379},
	year = {2021},
	pages = {20200116},
	abstract = {<p align="justify">Recently, they have received renewed attention for the design and optimal actuation of bioinspired robotic devices. We discuss a possible interpretation of these spontaneous oscillations as a Hopf-type bifurcation in a growing morphoelastic rod. Using a three-dimensional model and numerical simulations, we analyse the salient features of this flutter-like phenomenon (e.g. the characteristic period of the oscillations) and their dependence on the model details (in particular, the impact of choosing different growth models) finding that, overall, these features are robust with respect to changes in the details of the growth model adopted.\&nbsp;</p>},
	keywords = {circumutations, Gravitropism, Hopf bifurcation, morphoelastic rods},
	doi = {doi.org/10.6084/m9.figshare.c.5354189},
	author = {Daniele Agostinelli and Giovanni Noselli and Antonio De Simone}
}
@article {64,
	title = {Nutations in plant shoots: Endogenous and exogenous factors in the presence of mechanical deformations},
	journal = {Frontiers in Plant Science - Plant Biophysics and Modeling},
	volume = {12},
	year = {2021},
	pages = {371},
	abstract = {<p align="justify">We present a three-dimensional morphoelastic rod model capable to describe the morphogenesis of growing plant shoots driven by differential growth. We discuss the evolution laws for endogenous oscillators, straightening mechanisms and reorientations to directional cues, such as gravitropic reactions governed by the avalanche dynamics of statoliths. We use this model to investigate the role of elastic deflections due to gravity loading in circumnutating plant shoots. We show that, in the absence of endogenous cues, pendular and circular oscillations arise as a critical length is attained, thus suggesting the occurrence of an instability triggered by exogenous factors. When also oscillations due to endogenous cues are present, their weight relative to those associated with the instability varies in time as the shoot length and other biomechanical properties change. Thanks to the simultaneous occurrence of these two oscillatory mechanisms, we are able to reproduce a variety of complex behaviors, including trochoid-like patterns, which evolve into circular orbits as the shoot length increases, and the amplitude of the exogenous oscillations becomes dominant.</p>},
	keywords = {3d morphoelastic rods, circumnutation, Differential growth, plant morphogenesis, two-oscillator hypothesis},
	doi = {10.3389/fpls.2021.608005},
	author = {Daniele Agostinelli and Antonio DeSimone and Giovanni Noselli}
}
